Cats refuse to take the real baths; the act of licking themselves with their tongues is their version of bathing. Of course to see drowning cats or drowning kittens would then have great significance since they are rarely seen in these sorts of situations. As a dream symbol this carries with it some intense logic that must be sorted through to be understood.
If you have a dream in which you see a drowning cat, this might mean that you feel like your sense of independence is being suffocated by someone else, or that your sense of independence is being challenged by someone else and their dependence on you. A cat is a symbol of independence and self reliability. Water is something that is associated with emotion, so to dream of a cat drowning means that your sense of individuality and independence is being stifled by someone else getting all up in your business. Maybe someone in your life has been monopolizing your time too much because they have been sad recently. Sometimes all you need to do is just pull up your bootstraps and make sure that they know that you need your own time. You need to be able to have your own life and as much as you might want to help them and as much as they need you to help them, you can only help so much before their emotions start to wear you out too.
Kittens are known for their sense of playfulness and their sense of innocence. If you have a dream in which you are drowning kittens then this means that something has happened recently which has put you in a very serious mood, and you are not receptive to the antics of others. You are done with the whole debacle and you are ready to get down to the part of it that really matters. Do away with all of the frills and the playfulness and get right to business in your future conversations; this is what will make you feel better.